Rotary compressor injection cooling arrangement



Oct. 1, 1963 P. J. DELLARIO 3,105,633

ROTARY COMPRESSOR INJECTION coouuc ARRANGEMENT Filed Sept. 20, 1961 2 Sheets-Sheet 1 FIG. I

INVENTOR. PATRICK J. DELLA RIO Oct. 1, 1963 P. J. DELLARIO 3,105,633

ROTARY COMPRESSOR INJECTION cooumc ARRANGEMENT Filed Sept. 20. 1961 2 Sheets -Sheet 2 FIG}.

INVENTOR PATRICK J DELLARIO WWW 3,105,633 RQTARY COMPRESSGR INJECTION COOLHIG ARRANGEMENT Patrick J. Deilario, Louisviile, Ky., assignor to General Electric Company, a cerporation of New York Filed Sept. 26, 1961, Ser. No. 139,514 i Claims. (ill. 230139) The present invention relates to rotary compressors and more particularly to an arrangement for supplying condensed liquid refrigerant to the compression chamber of a rotary compressor for cooling the gases during the compression thereof.

It is common practice in the field of refrigeration to mount both the refrigerant compressor and its drive motor within a hermetically sealed casing. in such an arrange meet it is necessary to provide some means for cooling the drive motor in order to maintain its temperature within practical operating limits. One means employed for this purpose is to pass the high pressure discharge gas from the compressor unit over the compressor motor after the high pressure gas has been cooled to a low enough temperature to remove heat from the motor as it passes thereover. The heat removed from the motor is carried oil by the high pressure discharge gas and dissipating in the condenser of the refrigerating system. This is an efficient method for maintaining the motor at a proper operating temperature but requires that the high pressure discharge gas be precooled before it is passed into intimate contact with the motor.

One means for cooling the high pressure discharge gas before it is passed over the motor is to cool it in a superheat removal coil which is connected to the discharge outlet of the compressor unit and which extends outside of the hermetic casing into the outside ambient. The high pressure gas flows from the compressor into the superheat removal coil and is cooled by the air before being passed into the case and over the motor. The incorporation of a superheat removal coil onto the hermetic casing creates a sealing problem and, in addition, the intermittent discharge pulses of the high pressure gas flowing through the coil sometimes cause audible vibrations that are transmitted from the coil to the supporting structure.

Another means for cooling the discharge gas before passing it over the motor is to mix a small amount of liquid refrigerant from other portions of the system with this discharge gas prior to passing over the motor. The liquid refrigerant flashes into gaseous form and mixes with the discharge gas thereby cooling it sufficiently to remove heat from the motor. However, in this type of arrangement, some means must be provided for reducing the pressure at the outlet of the liquid supply conduit in order to obtain flow of liquid refrigerant from the source into the high pressure discharge gas.

An arrangement for accomplishing injection of liquid refrigerant into the high pressure gas is disclosed in the invention of the application of Dean C. Rinehart, Serial No. 139,447, filed concurrently with the present application, and assigned to General Electric Company, the assignee of the present application. The present invention is an improvement over the invention of the said Dean C. Rinehart which was made prior to the present invention and nothing is herein claimed as my invention that is shown or described in the Rinehart application, which is to be regarded as prior art with respect to this present a plication.

In the aforementioned Rinehart invention, the pressure drop in the refrigerant line from the hermetic case to the source of condensed refrigerant in the condenser of the system is overcome by injecting liquid into the compression chamber through an injection port that is open to the chamber only at such times when the pressure of the EdhSfiiZi Patented Get. 1, 1963 gas in the chamber is lower than the pressure in the condenser of the refrigeration system.

It is an object of the present invention to provide an improved arrangement for injecting liquid refrigerant into the compression chamber of the rotary refrigerant compressor so that the liquid refrigerant is effectively mixed with the semi-compressed gases within the compression chamber rior to discharge of the gas mixture from the chamber.

Further objects and advantages of the invention will become apparent as the following description proceeds, and the features of novelty which characterize the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

In carrying out the objects of the present invention there is provided a hermetically sealed refrigerant gas compressor unit adapted for use in a refrigeration system which normally includes a condenser for condensing refrigerant from the compressor and an evaporator for evaporating the condensed refrigerant. The compressor unit and its drive motor are mounted within a hermetically sealed case into which the compressor unit discharges its compressed refrigerant which then flows over the motor prior to passing into the condenser of the refrigeration system. The compressor unit includes a cylinder having an annular compression chamber and end walls enclosing opposite sides of the chamber. A shaft extending from the motor through one end wall of the chamber'drives a rot-or in an eccentric motion around the chamber so that.

the peripheral surface of the rotor moves progressively into sealing engagement with successive portions of the annular chamber. Means are provided between the outer periphery of the rotor and the surface of the annular chamber for dividing the chamber into high and low pressure sides during rotation of the rotor. Low pressure gas is delivered into the low pressure side of the chamber and compressed during the eccentric rotation of the rotor around the chamber and then discharged through a passage leading into the hermetic casing where it flows over the motor for cooling purposes. In order to maintain the temperature of the discharge gas sufficiently low to provide cooling for the motor, means are provided for injecting liquid refrigerant into the chamber including a liquid refrigerant injection port in one end wall of the chamber and so constructed and arranged with respect to' the end of the rotor as to be covered and uncovered thereby during the compression cycle of the rotor. In order to assure complete mixing of the liquid refrigerant with the semi-compressed gas within the chamber the axis of the injection port is slanted so that the liquid refrigerant is discharged in a direction opposite to the direction of rotation of the rotor during the compression cycle of the rotor. e

For a better understanding of the invention, reference may be had to the accompanying drawings in which:

FIGURE 1 is a side elevational view partially in crosssec-tion of a hermetic refrigeration compressor incorporating the present invention;

FIGURE 2 is a partial plan view taken along line 22 of FIGURE 1;

FIGURE 3 is a schematic view of :a refrigeration sysis disposed a refrigerant compressor unit 3 having an annular. chamber or compression chamber 4 defined within a cylinder or housing 5. Disposed for rotation Within the chamber 4 is a rotor 6 which is driven by an eccentric 7 formed as an integral part of the drive shaft 8 extending downwardly from the motor 9. A bearing 11 formed in the supporting main frame 12, supports the shaft 8 above the eccentric 7 for rotation by thernotor. It should be noted that the upper end wall enclosing the annular chamber 4 is provided by the main frame 12. The main frame 12 also supports the compressor unit 3 within the hermetic casing. The opposite or lower end wall of the compressor chamber 4 is formed by a bearing plate which also supports the lower end of the shaft 8 in a bearing Mia.

As may best be seen in FIGURE 2, the cylinder 5 is provided with a radial slot 13 having slidably disposed therein a blade or vane 14 which is biased into engagement with the peripheral surface 6:: of the rotor 6 thereby dividing the chamber 4 into low and high pressure sides respectively designated 4a and 4b. In the illustrated embodiment of the invention, the end of the blade 14 is biased against the periphery of the rotor by means of a spring 16 arranged within an enlarged opening 13a forming the rear part of the radial slot 13. During operation of the unit, the rotor 6 is eccenttrically rotated within the chamber by the eccentric 7 so that the peripheral surface 6a of the rotor moves progressively in the sealing relation with successive portions of the annular chamber thereby forcing gas ahead of it in the direction of rotation as is well known in the art.

As may be seen in FIGURE 3, the hermetic compressor 1 is adapted to be connected into a refrigeration system to receive suction gas from an evaporator through a suction line 20. Means are provided for delivering the suction gas into the low pressure side 4a of the annular chamber 4 from the suction line More specifically, referring to FIGURE 2, these means include a suction port 17 formed in the cylinder 5 and communicating with the annular chamber 4. The suction port 17 delivers low pressure gas into the low pressure side 4a of the compression chamber where it is compressed between the peripheral surface of the rotor 6, the sides of the annular chamber, and the high pressure side lda of the vane 14 during rotation of the rotor 6 around the chamber.

Means including a discharge port 18 and discharge chamber 19, are provided for directing the high pressure gas from the high pressure side 4!] of the annular chamber 4 into the hermetic casing 2. Mounted within the dis charge chamber 19 is a suitable valve 21 for assuring proper compresison of the gas issuing through the discharge port 18 and for preventing reverse flow of gas back into the compression chamber 4. As may be seen in FIGURE *1, the high pressure gas from the discharge chamber 19 flows into the hermetic casing 2 through a passage 25 formed in the main frame 12, or formed in the upper end Wall of the compressor unit. After flowing upwardly over the motor 9, the high pressure gas is conducted out of the hermetic casing 2 through a'suitable discharge means or outlet in the upper end of the case. The gas then flows through the discharge line (shown only in FIGURE 3) into the condenser 22 Where the heat absorbed by the refrigerant in the other portions of the system is extracted. As the gas in the condenser 22 is cooled, it condenses so that the refrigerant in the latter stage of the condenser is, therefore, largely in liquid form. A suitable expansion means is provided between the condenser and the evaporator for expanding liquid refrigerant from condenser pressure to evaporator pressure during operation of the system. In the illustrated embodiment of the invention, the expansion means comprise a capillary 23 located between the condenser 15 and evaporator 22 of the system.

Referring again to FIGURE 1, there is shown an ar rangement whereby lubricating oil is provided for the various bearing surfaces and other moving parts of the unit. As may be seen in FIGURE 1, a reservoir or body of lubricant 24 in the lower portions of the hermetic cas ing. This body of lubricant or oil is of suflicient depth to cover the lower end of the shaft 8 and a portion of the lower end wall 10 of the compressor unit so that these members are substantially immersed in the lubricating oil. 7 Means are provided for pumping lubricant into various moving parts of the compressor unit. More specifically, these means include a relatively large axially extending passage 26 in the shaft 8 which receiveslubricant through the opening in the bottom of the bearing plate 10 which, as stated previously is immersed in the lubricant. Upon rotation of the shaft, lubricant entering the axial passage 26 is forced to quickly assume the rotational speed of the shaft 8 and centrifugal force then causes thelubricant to flow outwardly against the inner surfacerof the axial passage 26 and upwardly along the inner passages.

Suitable oil outlets provided along the circumference of the shaft transmit lubricant to the various bearings of the compressor. Oil return passages 27 and 28 in the bottom plate It and in the main frame 12 respectively pro-' vide means for returning excess oil to the oil sump 24 in the lower regions of the case. The oil is continually circulated through the moving parts of the compressor and is therefore constantly in contact with the hot gases in the case as well as with the moving parts of the compressor. The body of lubricant, therefore, becomes relatively hot.

A compressor of the above-described type, when tested in an air conditioning unit in which 'air at approximately F. was circulated over the evaporator and air at approximately F. was circulated over the condenser,

produced a refrigerant gas pressure within the hermetic case of approximately 300 p.s.i.g. The pressure within the high pressure side 4!) of the annular chamber reached the maximum of 330 p.s.i.g. The suction pressure in a refrigeration system of this type normally runs approxisure of the gas within the case, but as can be seen from] the above-representative figures, pressure within the hermetic case 2 is substantially above that of suction. pressure. As the suction pressure is compressed within the chamber from 75 p.s.i.g. to 330 p.s.i.g. there is a substantial increase in temperature of this gas during compression. For example, in the tested refrigeration system, the gas temperature increased from approximately 70 F. to a discharge temperature of approximately 250 F. which, under most conditions of operation, is too great to carry the motor heat away from the motor at a rate calculated to assure proper motor operating temperatures. If the gas is permitted to continually discharge at any temperature above 200 F., there is likely to be insufficient cooling of the motor and damage to the motor insulation or windings is likely to occur.

In order to assure that the temperature of the discharge gas is sufiiciently low to properly cool the motor as the gas is circulated thereover, the present invention providesmeans for injectinga small quantity of liquid refrigerant into the compression chamber 4 during each compression cycle of the rotor. mixes with the semi-compressed gas in the high pressure side of the chamber and greatly reduces the discharge temperature of this gas. More specifically, there is pro} vided an injector port 31 arranged on the high pressure side 4b of the compression chamber 4. In the preferred embodiment of the invention, the port 31 is so arranged with respect to the high pressure side ib of the compres sion chamber 4 and with respect to the rotor 6 that the end 32' of the rotor 6 completely covers the outlet of The liquid refrigerant the port 31 at all times during each cycle of the rotor except for a short period during each cycle when the gas pressure in the high pressure side 4b of the compression chamber 4 is between 50% and 95 of discharge pressure.

As may be seen in FIGURES 1 and 3, means are provided for introducing liquid refrigerant into the injection port from a source of condensed refrigerant in the refrigeration system. In the illustrated embodiment of the invention, liquid refrigerant is introduced into the injection port 31 through a passage which includes the line or conduit 33 connecting with the condenser 22 in the latter stages thereof where the refrigerant is normally in liquid form. As may be seen in FIGURE 1, in addition to the conduit 33, the passage includes a larger tube 34 which enters the case 2 and passes upwardly through the oil sump 24 in the bottom of the hermetic case 2. The tube 34 is attached to the bottom plate by means of a connecting stud 35 containing an aperture in alignment with the injection port 31. A small capillary or tube 36 extends from the center of the stud 35 into the lower regions of the tube 34 where it is constantly immersed in liquid refrigerant within the tube 34 and completes the liquid refrigerant supply passage to the injector port 31. It will be noted that the opening between the tube 33 and the tube as permits liquid refrigerant to flow into the larger tube 34. This ar angement provides a liquid refrigerant reservoir covering the end of the tube 36 and creates a refrigerant gas trap or expansion chamber 34:: within the larger tube 34. The expansion chamber 34a serves to damp liquid impulses or vibrations created by the intermittent opening and closing of the injector port 31 during rotation of the rotor 6 around the compression chamber 4.

Referring now to the schematic diagram of FIGURE 4, it may be seen that the injection port 31 is closed at all times during the compression cycle of the rotor 6 ex cept during the period when the contacting or peripheral surface 6a of the rotor moves from point A to point C of the annular chamber 4. As will be noted in FIGURE 4, the location of the outlet of the injection port 31 of the illustrated compressor is adjacent the high pressure side 14a of the blade 14 on a line 37 passing through the center of the chamber and at an angle of approximately 12 with respect to the center line 38 of the blade 14. It will be noted that when the peripheral surface 6a of the rotor engages point A of the chamber, the end 32 of the rotor 6 is just beginning to uncover the liquid injection port 31. When the peripheral surface 6a is at point C, the rotor has again closed the port 31. In the illustrated embodiment of the invention, the location of point A is approximately 245 in advance of the completion of the compression stroke or in advance of the center line 38 of the blade 14. In a tested compressor unit having the relative dimensions of the compressor shown in the drawings, the pressure of the gas within the high pressure side 4b of the chamber, when the rotor surface 6a engages point A, was approximately 160 p.s.i.g. or approximately 56 of the pressure of the gas within the hermetic case 2. Point C is located approximately 140 in advance of the completion of the compression stroke or in advance of the center line 38 of the blade 14. When the peripheral surface of the rotor of the tested compressor engaged point C, the pressure within the high pressure side 4b of the chamber was approximately 290 p.s.i.g., which is about 95% of the pressure within the hermetic case 2. Thus the injection port is opened when the pressure within the compression chamber is between 50% and 95% of the pressure within the case. It should be noted that the injection port 31 is closed whenever the pressure within the compression chamber exceeds 290 p.s.i.g. or exceeds that of the case, which is only slightly above the pressure within the condenser from which the liquid refrigerant flowing into the injector port 31 is supplied. The average pressure of the gas within the compression side 4b of the chamber 4 when the opening of the liquid injection port was unsealed by the end 32 of the rotor, was about 225 p.s.i.g. This is only an average of p.s.i.g. below discharge pressure and, although it permits some expansion or flashing of the liquid refrigerant being injected into the expansion chamber to cool the gas being compressed therein, it does not too greatly effect the efiiciency of the compressor.

However, the pressure within the compression chamber, when the injection port is uncovered, is always below that within the condenser 22 so that liquid refrigerant is induced to flow through the liquid refrigerant supply passage toward the relatively lower pressure of the compression chamber to be injected into the chamber. Yet, the location of the injection port 31 with respect to the rotor 6 is such that, before liquid injection occurs, the pressure within the chamber is much above suction pressure, or, as stated previously, is approximately 50% of case pressure. This prevents flooding of the compression chamber with liquid refrigerant which, of course, would affect the efiiicency of the compressor unit.

It will be noted that, at all times during injection of liquid refrigerant into the compression chamber, the suction port 17 is sealed by the peripheral surface 6a of the rotor from that portion of the chamber into which the liquid refrigerant is being injected. That is, the peripheral surface 6a in contact with the annular chamber 4 has moved past the edge 17a of the suction port 17 and liquid refrigerant is only injected into the high pressure side of the chamber. Thus all of the suction gas trapped in the high pressure side 4b of the chamber is within the chamber at the time that the liquid refrigerant is injected therein for cooling purposes.

Because the discharge outlet '18 must necessarily be close to the end of the compression stroke or cycle of the rotor and because, as described above, the most desirable injection period is obtained by locating the injection port 3-1 at some point close to the high pressure side 14a of the blade 14. The injection port 31 is, therefore, necessarily arranged in the proximity of the discharge outlet 18. It has been found desirable to construct and arrange the injection port 31 so that it discharges liquid refrigerant in a direction toward the rotor or toward the gas being compressed which is in a state of high turbulence as being compressed by the rotor. More specifically, it has been found desirable to direct the injected liquid refrigerant in a direction away from the discharge port 18 so that it will rnix effectively with the gas being compressed before being passed out of the chamber with the discharge gas. Thus liquid refrigerantis injected into the semi-compressed gas as it is forced around the chamber toward the high pressure side 14a of the blade. More specifically, as may be seen upon reference to FIGURE 5, the injection port 31 of the present invention is arranged with its axis 40 at an acute angle with respect to the surface 10b of the end wall 16 of the chamber, and lying generally circumferentally with respect to said chamber. This is an acute angle having its opening facing circumferentially in a direction away from the blade 14 as shown in FIGURE 5 so that the liquid refrigerant is discharged directly toward the turbulent gas being forced around the annular chamber toward the blade or in a direction opposite to the direction of rotation of the rotor. During each compression cycle, when cooled liquid refrigerant is discharged into the oncoming relatively hot semi-compressed gas in the chamber 4b, it 'vaporizes or flashes into gaseous form and mixes with the compressed gas. Heat removed from the semi-compressed gas in vaporizing the liquid refrigerant greatly reduces the temperature of the gas within the chamber 4b so that the resultant gas issuing from the discharge port 18 and through the passage 25 is at a uniformly lower temperature than would be the case if the liquid refrigerant were not added.

In the illustrated embodiment of the invention, the

angle of the axis 4b is at 45* with respect to the surface lltib of the end wall of the chamber. By directing the liquid refrigerant discharging from the injection port 31 at an angle with respect to the end wall it of the chamher and toward the gas being forced around the chamber, or in the direction opposite the direction of rotation of the rotor or shaft 8, the discharge gas is directed away from the outlet port 18 and causes the injected liquid to mix completely with the semi-compressed gas before it is discharged from the chamber. While liquid refrigerant, when injected normal to the end wall 1% of the chamber, does cool the discharge gas, it has been found in a tested embodiment of the compressor that the temperature is lowered approximately 10 F. or more by discharging the liquid refrigerant toward semi-compressed gas as it is forced by the rotor around the chamber. It is believed that this additional cooling results from a more complete mixing of the liquid refrigerant with the semi-compressed gas while the gas is still in the chamber. though, it is true that unmixed liquid refrigerant which might be forced out the discharge outlet 18 does eventually vaporize and reduce the gas temperature, it is believed that more uniform cooling occurs when the liquid refrigerant is thoroughly mixed within the chamber t.

It has been found that, while an angle of 45 with respect to the surface Zlfib of the end wall 1d of the compressor unit is desirable, a discernible increase in cooling effect is provided over that occurring when discharge is normal to the wall surface 1% when the acute angle of the axis it? of the injection port 31 is as great as 60 from the surface All; of the end wall it of the annular compression chamber 4. It should be mentioned that the injection port Call is formed in a plane passing perpendicularly through the center line 37 arranged at approximately 12 with respect to the blade 14, as is indicated by FIGURE 5, which is a cross section of the compressor unit taken perpendicular to line 37. Therefore, it will be notedthat the injection port 31 is formed in a plane normal to the center line 37 passing through the center of the chamber and the outlet of the port. This plane is approximately tangent to the peripheral surface 6a of the rotor when the rotor has completely uncovered the injection port 31 or when the peripheral surface of the rotor is in the position indicated by the letter D in FIG- URE 5.

in a tested embodiment of the invention, the tempera ture of the gas discharging from the compression chamher in which liquid was injected into the upstream portions of the chamber was approximately 160 F. as compared to the aboveamentioned discharge temperature of 2l0230 when in a tested compressor in which liquid injection was not used. This high density gas at 160 F. temperature has sufficient cooling capacity, when passed over the motor, to remove sufficient motor heat to maintain the motor within practical operating temperatures. Furthermore, the reduction in temperature of this semi-compressed gas in the compression chamber 41) permits the gas to be more easily compressed and does not to any extent effect the efiiciency of the compressor.

While in accordance with the patent statutes there has been described what at present is considered to be the preferred embodiment of the invention, it will be obvious to those slrilled in the art that various changes and modifications may be made therein without departing from the invention and it is, therefore, the aim of the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A hermetically sealed refrigerant compressor" adapted for use in a refrigeration system comprising a hermetic casing adapted to contain a high pressure refrigerant gas, a compressor unit in said casing including a cylinder having an annular compression chamber and end walls enclosing the ends of said annular chamber, a rotor eccentrical'ly rotatable within said chamber, means within said chamber between the outer periphery of said rotor and the surface of said annular chamber for dividing said chamber into high and low pressure sides, means including a suction inlet opening communicating with said annu-lar chamber at said low pressure side of said dividing means for introducing low pressure refrigerant gas into said annular chamber, means including a gas discharge opening communicating with said annular chamber onsaid high pressure side of said dividing means for conducting hot compressed refrigerant gas from said chamber into said hermetic casing, a drive motor mounted within said hermetic casing, said motor having a shaft extending from said motor through one of said end walls of said cylinder for eccentrically driving said rotor around said chamber so that the peripheral surface of said rotor moves progressive-ly into sealing relation with successive portions of said annular chamber from said suction inlet opening toward said gas discharge opening thereby to drive refrigerant gas around said chamber to compress said gas therein toward said dividing means, means for injecting condensed liquid refrigerant into said annular chamber including a liquid refrigerant injection port in one end wall of said cylinder communicating with said chamber on the high pressure side of said dividing means, said liquid refrigerant injection port being so constructed and arranged that its discharge is covered and uncovered by the ends of said rotor during the eccentric rotation thereof around said chamber, said injection port having its discharge iaxis slanted circumferentially in a direction to discharge said liquid refrigerant circumferentially in a direcu'on away from said dividing means toward the advancing surface of said rotor as it compresses said gasthereby to direct said liquid refrigerant toward said semicompressed gas as it is forced by said rotor around said chamber toward said dividing means whenever said rotor uncovers said injection port so that said liquid refrigerant is thoroughly mixed with said gas prior to being discharged from said chamber.

2. A hermetically sealed refrigerant compressor adapted for use in a refrigeration system comprising a hermetic casing adapted to contain a high pressure refrigerant gas, a compressor unit in said casing including a cylinder having an annular compression chamber and end walls enclosing the ends of said annular chamber, a rotor eccentrically' rotatable within said chamber, a radial slot in said cylinder communicating with said chamber, a blade slida-bly positioned in said radial slot, means biasing said blade against the peripheral surface of said rotor for following said rotor thereby to divide chamber into a high pressure side on one side of said blade and a low pressure side on the other side of said blade, means including a suction inlet opening communicating with said annular chamber at said low pressure side of said blade for introducing low pressure refrigerant gas from said system into said chamber, means for including a gas discharge opening communicating with said annular chamber at said high pressure side of said blade for conducting compressed refrigerant gas from said chamber into said hermetic casing, a motor having a shaft extending through one of said end walls of said cylinder for eccentrically driving said rotor'around said chamber so that the peripheral surface ofsaidrotor moves progressively into sealing relation with successive portions of said annular chamber from said suction inlet I toward said gas discharge opening thereby to drive said refrigerant gas around said chamber toward said blade,

means for injecting condensed liquid refrigerant into said, annular chamber for cooling gas being compressed there in including a liquid refrigerant injection port in'one end wall of said cylinder, said liquid injection port being so constructed and arranged that its discharge end communioates with said chamber at a point closely adjacent'said high pressure side of said blade and to be covered anduncovered by the end of said rotor during the eccentric rotation of said rotor around said chamber, said injection port having a discharge axis inclined in said one end Wall at an acute angle with respect to said one end wall and directed circumferentially away from said blade so that liquid refrigerant is discharged in a direction away from said blade and toward said gas being driven around said chamber Whenever said rotor uncovers said port, and a liquid refrigerant supply passage connecting with said injection port for delivering liquid refrigerant to said port from a source of condensed refrigerant in said refrigeration system.

3 A hermetically sealed refrigerant compress-or adapted for use in a refrigeration system comprising a hermetic casing adapted to contain a high pressure refrigerant gas, a compressor .nnit in said casing including a cylinder having an annular compression chamber and end walls enclosing the ends of said annular chamber, a rotor eccentrically rotatable within said chamber, a drive motor also mounted in said hermetic case, a radial slot in said cylinder communicating with said chamber, a blade slidably positioned in said radial slot, means biasing said blade against the peripheral surface of said rotor for following said rotor thereby to divide said chamber into high and low pressure sides disposed on opposite sides of said blade, means including a suction opening adjacent the low pressure side of said blade communicating with said annular chamber for introducing low pressure refrigerant gas into said annular chamber, means including a gas discharge opening adjacent the high pressure side of said blade communicatin-g with said annular chamber for conducting hot compressed refrigerant gas from said chamber into said hermetic casing for cooling said motor, said motor having a shaft extending through one of said end walls of said cylinder for eccentrically driving said rotor around said chamber so that the peripheral surface of said rotor moves progressively into sealing relation with successive portions of said annular chamber from said suction opening toward said gas discharge opening thereby driving refrigerant gas around said chamber toward said blade, means for injecting condensed liquid refrigerant into said annular chamber for cooling said gas being compressed therein including a liquid refrigerant injection port in one end wall of said cylinder, said liquid refrigerant injection port being so constructed and arranged that its discharge end is covered and uncovered by the end of said rotor during the eccentric rotation of said rotor around said chamber, said injection port having its discharge axis slanting at an angle not greater than 60 with respect to said end wall and circumferential-1y with respect to said chamber so as to discharge liquid refrigerant away from said blade in a a direction opposite to the direction of rotation of said rotor when said rotor uncovers said injection port, and a liquid refrigerant supply passage connecting with said injection port for delivering liquid refrigerant to said port from a source of condensed refrigerant in said refrigeration system. v

4. A hermetically sealed refrigerant compressor adapted for use in a refrigeration system comprising a hermetic casing adapted to contain a high pressure refrigerant gas, a compressor unit in said casing including a cylinder having an annular compression chamber and end walls en-i closing the ends of said annular chamber, a rotor ec-. centrically rotatable Within said chamber, a radial slot in said cylinder communicating with said chamber, a blade slid-ably positioned in said radial slot, means biasing said blade against the peripheral surface of said rotor for following said rotor thereby to divide said chamber into high and low pressure sides disposed on opposite sides of said blade, means including a suction gas opening communicating with said annular chamber on one side of said blade ad-ajcent its low pressure side for introducing low pressure refrigerant gas into said annular chamber, means including a gas discharge opening on the other side of said blade communicating with said annular chamber adjacent the high pressure side of said blade for conducting hot compressed refrigerant gas from said chamber into said hermetic casing, a motor in said casing having a shaft extending through one of said end walls of said cylinder for cccentrically driving said rotor around said chamber so that the peripheral surface of said motor moves progressively into sealing relation with successive portions of said annular chamber from said suction gas opening toward said discharge opening thereby to drive refrigerant gas around said chamber toward said blade, means for injecting condensed liquid refrigerant into said annular chamber for cooling said gas being compressed therein including a liquid refrigerant injection port in one end Wall of said cylinder, said liquid refrigerant injection port being so constructed and arranged that its discharge end is covered and uncovered by the end of said rotor during the eccentric rotation of said rotor around said chamber, said injection port having its discharge axis slanting circumferentially with respect to said chamber in a direction away from said blade at an angle not greater than with respect to said end wall of said chamber and said injection port being formed in a plane substantially tangent to said peripheral surface of said rotor When said rotor completely uncovers said injection port so that liquid refrigerant is discharged approximately tangent to said rotor in a direction opposite to the rotation thereof away from said blade, and means connecting with said liquid injection port for delivering liquid refrigerant to said injection port from a source of condensed liquid refrigerant in said refirigera-tion system.

References Cited in the file of this patent UNITED STATES PATENTS 2,299,811 Feicht Oct. 27, 1942 2,929,550 Sadler Mar. 22, 1960 2,988,267 Kosfeld June 13, 1961 2,991,931 Galin July 11, 1961 FOREIGN PATENTS 678,962. Germany July 26, 1939 

1. A HERMETICALLY SEALED REFRIGERANT COMPRESSOR ADAPTED FOR USE IN A REFRIGERATION SYSTEM COMPRISING A HERMETIC CASING ADAPTED TO CONTAIN A HIGH PRESSURE REFRIGERANT GAS, A COMPRESSOR UNIT IN SAID CASING INCLUDING A CYLINDER HAVING AN ANNULAR COMPRESSION CHAMBER AND END WALLS ENCLOSING THE ENDS OF SAID ANNULAR CHAMBER, A ROTOR ECCENTRICALLY ROTATABLE WITIN SAID CHAMBER, MEANS WITHIN SAID CHAMBER BETWEEN THE OUTER PERIPHERY OF SAID ROTOR AND THE SURFACE OF SAID ANNULAR CHAMBER FOR DIVIDING SAID CHAMBER INTO HIGH AND LOW PRESSURE SIDES, MEANS INCLUDING A SUCTION INLET OPENING COMMUNICATING WITH SAID ANNULAR CHAMBER AT SAID LOW PRESSURE SIDE OF SAID DIVIDING MEANS FOR INTRODUCING LOW PRESSURE REFRIGERANT GAS INTO SAID ANNULAR CHAMBER, MEANS INCLUDING A GAS DISCHARGE OPENING COMMUNICATING WITH SAID ANNULAR CHAMBER ON SAID HIGH PRESSURE SIDE OF SAID DIVIDING MEANS FOR CONDUCTING HOT COMPRESSED REFRIGERANT GAS FROM SAID CHAMBER INTO SAID HERMETIC CASING, A DRIVE MOTOR MOUNTED WITHIN SAID HERMETIC CASING, SAID MOTOR HAVING A SHAFT EXTENDING FROM SAID MOTOR THROUGH ONE OF SAID END WALLS OF SAID CYLINDER FOR ECCENTRICALLY DRIVING SAID ROTOR AROUND SAID CHAMBER SO THAT THE PERIPHERAL SURFACE OF SAID ROTOR MOVES PROGRESSIVELY INTO SEALING RELATION WITH SUCCESSIVE PORTIONS OF SAID ANNULAR CHAMBER FROM SAID SUCTION INLET OPENING TOWARD SAID GAS DISCHARGE OPENING THEREBY TO DRIVE REFRIGERANT GAS AROUND SAID CHAMBER TO COMPRESS SAID GAS THEREIN TOWARD SAID DIVIDING MEANS, MEANS FOR INJECTING CONDENSED LIQUID REFRIGERANT INTO SAID ANNULAR CHAMBER INCLUDING A LIQUID REFRIGERANT INJECTION PORT IN ONE END WALL OF SAID CYLINDER COMMUNICATING WITH SAID CHAMBER ON THE HIGH PRESSURE SIDE OF SAID DIVIDING MEANS, SAID LIQUID REFRIGERANT INJECTION PORT BEING SO CONSTRUCTED AND ARRANGED THAT ITS DISCHARGE IS COVERED AND UNCOVERED BY THE ENDS OF SAID ROTOR DURING THE ECCENTRIC ROTATION THEREOF AROUND SAID CHAMBER, SAID INJECTION PORT HAVING ITS DISCHARGE AXIS SLANTED CIRCUMFERENTIALLY IN A DIRECTION TO DISCHARGE SAID LIQUID REFRIGERANT CIRCUMFERENTIALLY IN A DIRECTION AWAY FROM SAID DIVIDING MEANS TOWARD THE ADVANCING SURFACE OF SAID ROTOR AS IT COMPRESSES SAID GAS THEREBY TO DIRECT SAID LIQUID REFRIGERANT TOWARD SAID SEMICOMPRESSED GAS AS IT IS FORCED BY SAID ROTOR AROUND SAID CHAMBER TOWARD SAID DIVIDING MEANS WHENEVER SAID ROTOR UNCOVERS SAID INJECTION PORT SO THAT SAID LIQUID REFRIGERANT IS THOROUGHLY MIXED WITH SAID GAS PRIOR TO BEING DISCHARGED FROM SAID CHAMBER. 